By the time you reach your third trimester, your little i is eavesdropping on your conversations, hearing the sound of your heartbeat, and even enjoying the music you heed to. But it takes a while for this to happen, and at that place are many steps forth the fashion. Find out how your infant'south ears and hearing develop within the womb.

When can a fetus hear?

Between 16 and 22 weeks of pregnancy, your baby may start to hear faint sounds within your torso such as the noise made by your breathing, heartbeat, and digestion. These sounds will grow louder as your baby'south hearing improves.

After 23 weeks, your babe tin hear sounds from the outside globe, including your vocalism. At first, your babe's ears tin hear just low-pitched sounds, meaning babies in the womb tin can generally hear male voices ameliorate than female voices. Even so, your ain vocalization will sound loud to your baby because it's close and reverberates through your body as y'all speak. Research shows babies learn to recognize their mother's voice inside the womb, and evidence a articulate preference for her voice over others.

Equally your infant's ears and brain mature, they'll gradually perceive a wider range of sounds, including more voices in the college ranges.

At around 26 weeks, your babe may begin to respond to the sounds they hear with changes in their heartbeat, breathing, and movement. If the noise is particularly loud, your baby may startle – and you might feel your baby movement. Ultrasounds have besides defenseless changes in babies' facial expressions when they hear music.

illustration of hearing development in fetus

When exercise babies develop ears?

Your baby's ears start developing in the get-go weeks of pregnancy, and aren't fully formed until the third trimester. The ear is a remarkably complex organ, with three separate parts (the inner ear, center ear, and outer ear). Each of these structures develops on its own timetable.

  • Inner ear development. Past v weeks of pregnancy, 2 pocket-size spots appear on either side of your baby's head – these somewhen become the inner ears. Presently they'll start to fold inwards and form sacs but below the surface of your baby'south skin. The sacs then lengthen into a tube, and the main organ of hearing (cochlea) takes shape at the terminate.
  • Middle ear development. Around eight weeks of pregnancy, the ear basic – tiny structures that vibrate and help process sounds – begin as pocket-size clumps of tissue that slowly harden over the coming weeks. A tube-like cavity that will go the heart ear begins to form around these structures.
  • Ear-brain connection. Around 12 weeks of pregnancy, specialized sound transmitters chosen pilus cells spring up inside the cochlea and somewhen connect to a nerve that sends audio impulses to the encephalon. This connection is made at about xvi weeks, when your baby may start to hear faint sounds.
  • Ears fully formed. By 32 to 35 weeks of pregnancy, the centre ear cavity, outer ear culvert, and outside role of the ear are fully formed. Your baby is ready to listen and respond to the sounds they'll hear as soon every bit they're born.

What babies hear in the womb

The noises and voices your infant hears from the outside world audio muffled. That's considering they have to pass through multiple layers, including your pare and the wall of your uterus besides as the amniotic fluid. Plus, it's noisy within your uterus – sounds from your breathing, heartbeat, and digestion are as loud to your baby every bit a washing machine.

That said, your baby will hear your vox more clearly than all others. That'southward because the sound of your phonation reverberates through your torso when you speak. Research suggests babies in the womb may become more alert when they hear their mom talking or reading aloud.

Sounds your babe hears in the womb contribute to hearing and brain evolution, which will go on once your infant is born. You and your partner don't demand to practice anything special to facilitate this.

How to back up your infant's hearing during pregnancy

You can accept steps to protect your babe'south hearing such as:

  • Exist careful with medications. Taking certain drugs during pregnancy, including some antibiotics, has been linked to hearing loss in babies. Tell all your health care providers (even your dentist) that you're meaning, and talk to your doctor or midwife to make sure y'all're taking safe medications for pregnancy.
  • Avoid prolonged, very loud noise. There's some evidence that long-term exposure to very loud dissonance – like 8 hours a twenty-four hours, every day – tin damage your baby'southward hearing. Some experts recommend fugitive whatsoever routine racket louder than 115 decibels (about every bit loud every bit a chainsaw) while pregnant. Information technology'due south all-time to avoid any noises louder than that, such equally a rock concert or shooting range, as much every bit possible. That'south truthful even if you're wearing hearing protection, because the dissonance tin withal travel through your body to your infant'south ears. If you piece of work in a very loud environment (say with noisy machinery or at loud events) you may want to ask your employer if you can piece of work in a quieter location for the duration of your pregnancy.
  • Swallow fish that's low in mercury. Fish is full of healthy omega-3 fatty acids that help your baby'south brain grow and develop, but some kinds also contain high levels of mercury – which has been linked to certain birth defects, including hearing loss. To rest these risks and benefits, the U.Southward. Food and Drug Assistants advises pregnant women to eat 8 to 12 ounces a calendar week of depression-mercury fish. Consume a variety of condom fish (such as salmon, cod, shrimp, and tilapia), and avoid the four types of fish that have the highest amounts of mercury: swordfish, tilefish, shark, and king mackerel.
  • Don't drinkable alcohol. Drinking during pregnancy tin cause a group of nascence defects known as fetal alcohol spectrum disorders (FASDs). Children with an FASD tin have hearing loss and trouble with speech. No one knows how much booze information technology takes to crusade the condition, so it's all-time to be on the condom side and avoid alcohol altogether.
  • Play music. There's no prove to support the myth that playing Mozart or other music for your baby in utero will make them smarter. All the same, evidence suggests listening to music (as well as people talking and other sounds from the environment) can help develop your baby'southward hearing, retentivity, and emotions. To protect your babe's fragile ears, make sure the music isn't also loud. Never place ear or head phones directly on your belly, as the sound volition amplify to unsafe levels every bit it travels to your baby.

Milestones in babe hearing development

Weeks significant What's happening
5 weeks Inner ear starts to develop.
12 weeks The cochlea and eye ear are forming, and hair cells brainstorm to sprout.
sixteen-22 weeks Your babe can hear sounds within your torso, similar your eye beating.
23 weeks Your baby can hear sounds from the outside world, similar a dog barking.
26 weeks Your baby tin hear a broader range of sound and can respond with changes in heartbeat, breathing, and movement.
32-35 weeks All parts of the ear are completely formed, and your baby's hearing continues to be fine-tuned.

Learn more:

  • Video: How your baby's sense of hearing develops
  • Music and your unborn child
  • Slideshow: Fetal evolution, week by week